/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/*
* The general pattern of use here:
* 1) Construct a minijail with minijail_new()
* 2) Apply the desired restrictions to it
* 3) Enter it, which locks the current process inside it, or:
* 3) Run a process inside it
* 4) Destroy it.
*/
#ifndef _LIBMINIJAIL_H_
#define _LIBMINIJAIL_H_
#include <stdint.h>
#include <sys/resource.h>
#include <sys/types.h>
#ifdef __cplusplus
extern "C" {
#endif
enum {
MINIJAIL_ERR_PRELOAD = 252,
MINIJAIL_ERR_JAIL = 253,
MINIJAIL_ERR_INIT = 254,
};
struct minijail;
/*
* A hook that can be used to execute code at various events during minijail
* setup in the forked process. These can only be used if the jailed process is
* not going to be invoked with LD_PRELOAD.
*
* If the return value is non-zero, it will be interpreted as -errno and the
* process will abort.
*/
typedef int (*minijail_hook_t)(void *context);
/*
* The events during minijail setup in which hooks can run. All the events are
* run in the new process.
*/
typedef enum {
/* The hook will run just before dropping capabilities. */
MINIJAIL_HOOK_EVENT_PRE_DROP_CAPS,
/* The hook will run just before calling execve(2). */
MINIJAIL_HOOK_EVENT_PRE_EXECVE,
/* The hook will run just before calling chroot(2) / pivot_root(2). */
MINIJAIL_HOOK_EVENT_PRE_CHROOT,
/* Sentinel for error checking. Must be last. */
MINIJAIL_HOOK_EVENT_MAX,
} minijail_hook_event_t;
/* Allocates a new minijail with no restrictions. */
struct minijail *minijail_new(void);
/*
* These functions add restrictions to the minijail. They are not applied until
* minijail_enter() is called. See the documentation in minijail0.1 for
* explanations in detail of what the restrictions do.
*/
void minijail_change_uid(struct minijail *j, uid_t uid);
void minijail_change_gid(struct minijail *j, gid_t gid);
/* Copies |list|. */
void minijail_set_supplementary_gids(struct minijail *j, size_t size,
const gid_t *list);
void minijail_keep_supplementary_gids(struct minijail *j);
/* Stores user to change to and copies |user| for internal consistency. */
int minijail_change_user(struct minijail *j, const char *user);
/* Does not take ownership of |group|. */
int minijail_change_group(struct minijail *j, const char *group);
void minijail_use_seccomp(struct minijail *j);
void minijail_no_new_privs(struct minijail *j);
void minijail_use_seccomp_filter(struct minijail *j);
void minijail_set_seccomp_filter_tsync(struct minijail *j);
void minijail_parse_seccomp_filters(struct minijail *j, const char *path);
void minijail_parse_seccomp_filters_from_fd(struct minijail *j, int fd);
void minijail_log_seccomp_filter_failures(struct minijail *j);
/* 'minijail_use_caps' and 'minijail_capbset_drop' are mutually exclusive. */
void minijail_use_caps(struct minijail *j, uint64_t capmask);
void minijail_capbset_drop(struct minijail *j, uint64_t capmask);
/* 'minijail_set_ambient_caps' requires 'minijail_use_caps'. */
void minijail_set_ambient_caps(struct minijail *j);
void minijail_reset_signal_mask(struct minijail *j);
void minijail_namespace_vfs(struct minijail *j);
void minijail_namespace_enter_vfs(struct minijail *j, const char *ns_path);
void minijail_new_session_keyring(struct minijail *j);
void minijail_skip_setting_securebits(struct minijail *j,
uint64_t securebits_skip_mask);
/*
* This option is *dangerous* as it negates most of the functionality of
* minijail_namespace_vfs(). You very likely don't need this.
*/
void minijail_skip_remount_private(struct minijail *j);
void minijail_remount_mode(struct minijail *j, unsigned long mode);
void minijail_namespace_ipc(struct minijail *j);
void minijail_namespace_uts(struct minijail *j);
int minijail_namespace_set_hostname(struct minijail *j, const char *name);
void minijail_namespace_net(struct minijail *j);
void minijail_namespace_enter_net(struct minijail *j, const char *ns_path);
void minijail_namespace_cgroups(struct minijail *j);
/* Closes all open file descriptors after forking. */
void minijail_close_open_fds(struct minijail *j);
/*
* Implies namespace_vfs and remount_proc_readonly.
* WARNING: this is NOT THREAD SAFE. See the block comment in </libminijail.c>.
*/
void minijail_namespace_pids(struct minijail *j);
void minijail_namespace_user(struct minijail *j);
void minijail_namespace_user_disable_setgroups(struct minijail *j);
int minijail_uidmap(struct minijail *j, const char *uidmap);
int minijail_gidmap(struct minijail *j, const char *gidmap);
void minijail_remount_proc_readonly(struct minijail *j);
void minijail_run_as_init(struct minijail *j);
int minijail_write_pid_file(struct minijail *j, const char *path);
void minijail_inherit_usergroups(struct minijail *j);
/*
* Changes the jailed process's syscall table to the alt_syscall table
* named |table|.
*/
int minijail_use_alt_syscall(struct minijail *j, const char *table);
/* Sets the given runtime limit. See getrlimit(2). */
int minijail_rlimit(struct minijail *j, int type, rlim_t cur, rlim_t max);
/*
* Adds the jailed process to the cgroup given by |path|. |path| should be the
* full path to the cgroups "tasks" file.
* Example: /sys/fs/cgroup/cpu/jailed_procs/tasks adds to the "jailed_procs" cpu
* cgroup.
*/
int minijail_add_to_cgroup(struct minijail *j, const char *path);
/*
* Install signal handlers in the minijail process that forward received
* signals to the jailed child process.
*/
int minijail_forward_signals(struct minijail *j);
/*
* minijail_enter_chroot: enables chroot() restriction for @j
* @j minijail to apply restriction to
* @dir directory to chroot() to. Owned by caller.
*
* Enters @dir, binding all bind mounts specified with minijail_bind() into
* place. Requires @dir to contain all necessary directories for bind mounts
* (i.e., if you have requested a bind mount at /etc, /etc must exist in @dir.)
*
* Returns 0 on success.
*/
int minijail_enter_chroot(struct minijail *j, const char *dir);
int minijail_enter_pivot_root(struct minijail *j, const char *dir);
/*
* minijail_get_original_path: returns the path of a given file outside of the
* chroot.
* @j minijail to obtain the path from.
* @chroot_path path inside of the chroot() to.
*
* When executing a binary in a chroot or pivot_root, return path to the binary
* outside of the chroot.
*
* Returns a string containing the path. This must be freed by the caller.
*/
char *minijail_get_original_path(struct minijail *j, const char *chroot_path);
/*
* minijail_mount_tmp: enables mounting of a 64M tmpfs filesystem on /tmp.
* As be rules of bind mounts, /tmp must exist in chroot.
*/
void minijail_mount_tmp(struct minijail *j);
/*
* minijail_mount_tmp_size: enables mounting of a tmpfs filesystem on /tmp.
* As be rules of bind mounts, /tmp must exist in chroot. Size is in bytes.
*/
void minijail_mount_tmp_size(struct minijail *j, size_t size);
/*
* minijail_mount_dev: enables mounting of a tmpfs filesystem on /dev.
* It will then be seeded with a basic set of device nodes. For the exact
* list, consult the minijail(0) man page.
*/
void minijail_mount_dev(struct minijail *j);
/*
* minijail_mount_with_data: when entering minijail @j,
* mounts @src at @dst with @flags and @data.
* @j minijail to bind inside
* @src source to bind
* @dest location to bind (inside chroot)
* @type type of filesystem
* @flags flags passed to mount
* @data data arguments passed to mount(2), e.g. "mode=755"
*
* This may be called multiple times; all mounts will be applied in the order
* of minijail_mount() calls.
*/
int minijail_mount_with_data(struct minijail *j, const char *src,
const char *dest, const char *type,
unsigned long flags, const char *data);
/*
* minijail_mount: when entering minijail @j, mounts @src at @dst with @flags
* @j minijail to bind inside
* @src source to bind
* @dest location to bind (inside chroot)
* @type type of filesystem
* @flags flags passed to mount
*
* This may be called multiple times; all mounts will be applied in the order
* of minijail_mount() calls.
*/
int minijail_mount(struct minijail *j, const char *src, const char *dest,
const char *type, unsigned long flags);
/*
* minijail_bind: bind-mounts @src into @j as @dest, optionally writeable
* @j minijail to bind inside
* @src source to bind
* @dest location to bind (inside chroot)
* @writeable 1 if the bind mount should be writeable
*
* This may be called multiple times; all bindings will be applied in the order
* of minijail_bind() calls.
*/
int minijail_bind(struct minijail *j, const char *src, const char *dest,
int writeable);
/*
* minijail_add_hook: adds @hook to the list of hooks that will be
* invoked when @event is reached during minijail setup. The caller is
* responsible for the lifetime of @payload.
* @j minijail to add the hook to
* @hook the function that will be invoked
* @payload an opaque pointer
* @event the event that will trigger the hook
*/
int minijail_add_hook(struct minijail *j,
minijail_hook_t hook, void *payload,
minijail_hook_event_t event);
/*
* minijail_preserve_fd: preserves _fd and makes it available as
* @child_fd in the child process. _fd will be closed if no other
* redirect has claimed it as a @child_fd. This works even if
* minijail_close_open_fds() is invoked.
* @j minijail to add the fd to
* _fd the fd in the parent process
* @child_fd the fd that will be available in the child process
*/
int minijail_preserve_fd(struct minijail *j, int parent_fd, int child_fd);
/*
* Lock this process into the given minijail. Note that this procedure cannot
* fail, since there is no way to undo privilege-dropping; therefore, if any
* part of the privilege-drop fails, minijail_enter() will abort the entire
* process.
*
* Some restrictions cannot be enabled this way (pid namespaces) and attempting
* to do so will cause an abort.
*/
void minijail_enter(const struct minijail *j);
/*
* Run the specified command in the given minijail, execve(2)-style.
* If minijail_namespace_pids() or minijail_namespace_user() are used,
* this or minijail_fork() is required instead of minijail_enter().
*/
int minijail_run(struct minijail *j, const char *filename,
char *const argv[]);
/*
* Run the specified command in the given minijail, execve(2)-style.
* Used with static binaries, or on systems without support for LD_PRELOAD.
*/
int minijail_run_no_preload(struct minijail *j, const char *filename,
char *const argv[]);
/*
* Run the specified command in the given minijail, execve(2)-style.
* Update |*pchild_pid| with the pid of the child.
*/
int minijail_run_pid(struct minijail *j, const char *filename,
char *const argv[], pid_t *pchild_pid);
/*
* Run the specified command in the given minijail, execve(2)-style.
* Update |*pstdin_fd| with a fd that allows writing to the child's
* standard input.
*/
int minijail_run_pipe(struct minijail *j, const char *filename,
char *const argv[], int *pstdin_fd);
/*
* Run the specified command in the given minijail, execve(2)-style.
* Update |*pchild_pid| with the pid of the child.
* Update |*pstdin_fd| with a fd that allows writing to the child's
* standard input.
* Update |*pstdout_fd| with a fd that allows reading from the child's
* standard output.
* Update |*pstderr_fd| with a fd that allows reading from the child's
* standard error.
*/
int minijail_run_pid_pipes(struct minijail *j, const char *filename,
char *const argv[], pid_t *pchild_pid,
int *pstdin_fd, int *pstdout_fd, int *pstderr_fd);
/*
* Run the specified command in the given minijail, execve(2)-style.
* Update |*pchild_pid| with the pid of the child.
* Update |*pstdin_fd| with a fd that allows writing to the child's
* standard input.
* Update |*pstdout_fd| with a fd that allows reading from the child's
* standard output.
* Update |*pstderr_fd| with a fd that allows reading from the child's
* standard error.
* Used with static binaries, or on systems without support for LD_PRELOAD.
*/
int minijail_run_pid_pipes_no_preload(struct minijail *j, const char *filename,
char *const argv[], pid_t *pchild_pid,
int *pstdin_fd, int *pstdout_fd,
int *pstderr_fd);
/*
* Fork, jail the child, and return. This behaves similar to fork(2), except it
* puts the child process in a jail before returning.
* `minijail_fork` returns in both the parent and the child. The pid of the
* child is returned to the parent. Zero is returned in the child. LD_PRELOAD
* is not supported.
* If minijail_namespace_pids() or minijail_namespace_user() are used,
* this or minijail_run*() is required instead of minijail_enter().
*/
pid_t minijail_fork(struct minijail *j);
/*
* Kill the specified minijail. The minijail must have been created with pid
* namespacing; if it was, all processes inside it are atomically killed.
*/
int minijail_kill(struct minijail *j);
/*
* Wait for all processes in the specified minijail to exit. Returns the exit
* status of the _first_ process spawned in the jail.
*/
int minijail_wait(struct minijail *j);
/*
* Frees the given minijail. It does not matter if the process is inside the
* minijail or not.
*/
void minijail_destroy(struct minijail *j);
/*
* minijail_log_to_fd: redirects the module-wide logging to an FD instead of
* syslog.
* @fd FD to log to. Caller must ensure this is available after
* jailing (e.g. with minijail_preserve_fd()).
* @min_priority the minimum logging priority. Same as the priority argument
* to syslog(2).
*/
void minijail_log_to_fd(int fd, int min_priority);
#ifdef __cplusplus
}; /* extern "C" */
#endif
#endif /* !_LIBMINIJAIL_H_ */